Coming from a person who's living in a country that's protesting every day:
Feel exhausted and not go protesting everyday
Not to go protesting because you have other responsibilities (for example your pet is having health problems or you have children who are too little to be left unattended)
Put your mental health as priority
Put your safety as priority
Contribute in any possible ways when you cannot attend protests in person: normalize the aim protesters fight for (for example in Poland many people who are opposing abortion ban can't imagine abortion being accessible to everyone for any reason, so it's important to talk about it), put the symbols of protest as profile picture, share the news, translate articles in another languages to inform foreigners, paint symbols of protest in public as stickers or paintings (just be careful and cover your face when doing so), doxx and send many emails/sms to spam the people who are oppressing the rest of society.
Using your privilege to help protestors
Shaming people for not protesting publicly
Being offended by "vandalism" such as graffiti or devastating statues
Ignoring protests and feelings of those who protest
Supporting protests and protestors only for your own gain
Supporting only partially (again, the same example as above: "abortion ban is wrong but abortion just because you don't want to have children is even worse" – extremely hurtful and mindless thing to say)
Trying to make money on symbols and protests (many Instagram influencers are advertising stuff using protests to do so. It's absolutely disgusting)